The trihybrid genome constitution of Bacillus lynceorum (Insecta Phasmatodea) and its karyotypic variations

Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 317-326 ◽  
Author(s):  
S. Manaresi ◽  
O. Marescalchi ◽  
V. Scali
Keyword(s):  
Silver Staining ◽  
Chromosomal Rearrangements ◽  
Centromeric Heterochromatin ◽  
Genome Constitution ◽  
C Banding ◽  
Centromeric Function ◽  
Stick Insects ◽  
Standard Karyotype ◽  
Staining Techniques

The standard karyotype and a wide array of repatterned cytotypes from 21 demes of the double-allotriploid thelytokous Bacillus lynceorum have been analyzed by means of Giemsa, C-banding, and silver-staining techniques. The present study substantially amends the first karyotype description and also analyzes in detail the chromosomal rearrangements to trace their most likely derivation. Bacillus lynceorum cytotypes also provide a well-documented instance of an intraspecific gain of centromeric function. The contribution of three different specific haplosets is particularly evidenced from centromeric heterochromatin pattern and satellite/Ag-NOR locations. In stick insects, both hybridogenetic and parthenogenetic Bacillus hybrids, including B. lynceorum, can utilize the rDNA of all available parental haplosets, although a hierarchical role of the B. rossius genome seems to emerge. Satellite/Ag-NOR patterns, besides clearly allowing the recognition of ancestral parental genomes, also suggest a polyphyletic origin for B. lynceorum, which, to our knowledge, represents the only described karyotype of a trihybrid invertebrate.Key words: Bacillus lynceorum, C-banding cytotypes, NOR hierarchy, centric fissions, thelytoky.

scholarly journals Cytogenetical analyses in three fish species of the genus Pimelodus(Siluriformes: Pimelodidae) from rio São Francisco: considerations about the karyotypical evolution in the genus

2005 ◽  
Vol 3 (2) ◽  
pp. 285-290 ◽  
Author(s):  
Caroline Garcia ◽  
Orlando Moreira Filho
Keyword(s):  
Chromosome Pair ◽  
Chromosomal Rearrangements ◽  
Nucleolar Organizer ◽  
Differential Staining ◽  
Nucleolar Organizer Regions ◽  
C Banding ◽  
Heteromorphic Sex Chromosomes ◽  
Chromosomal Markers ◽  
Staining Techniques ◽  
Species Specific

Karyotypes and other chromosomal markers were investigated in three species of the catfish genus Pimelodus, namely P. fur, P. maculatus and Pimelodus sp., from municipality of Três Marias, Minas Gerais, Brazil, using differential staining techniques (C-banding, Silver nitrate and CMA3 staining). The diploid chromosome number was 2n = 56 in P. maculatus and Pimelodus sp., while in P. fur 2n = 54. The karyotype of P. fur consisted in 32M + 8SM + 6ST + 8A with fundamental number (NF) of 100, that of P. maculatus 32M + 12SM + 12A with NF = 112, and that of Pimelodus sp. had 32M + 12Sm + 6ST + 6A with NF = 106.The nucleolar organizer regions (NORs) in all three species were invariably detected in telomeres of longer arm of the 20th chromosome pair. These sites were also positive after CMA3 and C-banding. No heteromorphic sex chromosomes were detected and C-banding pattern was species specific. Inferences about the karyotype differentiation in Pimelodus and putative chromosomal rearrangements are hypohesized.

scholarly journals The role of heterochromatin in the expression of a heterochromatic gene, the rolled locus of Drosophila melanogaster.

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 277-292 ◽  
Author(s):  
D F Eberl ◽  
B J Duyf ◽  
A J Hilliker
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosomal Rearrangements ◽  
Position Effect ◽  
Centromeric Heterochromatin ◽  
Position Effect Variegation ◽  
Position Effects ◽  
Major Function ◽  
Effect Variegation ◽  
Heterochromatic Genes

Abstract Constitutive heterochromatic regions of chromosomes are those that remain condensed through most or all of the cell cycle. In Drosophila melanogaster, the constitutive heterochromatic regions, located around the centromere, contain a number of gene loci, but at a much lower density than euchromatin. In the autosomal heterochromatin, the gene loci appear to be unique sequence genes interspersed among blocks of highly repeated sequences. Euchromatic genes do not function well when brought into the vicinity of heterochromatin (position-effect variegation). We test the possibility that the blocks of centromeric heterochromatin provide an environment essential for heterochromatic gene function. To assay directly the functional requirement of autosomal heterochromatic genes to reside in heterochromatin, the rolled (rl) gene, which is normally located deep in chromosome 2R heterochromatin, was relocated within small blocks of heterochromatin to a variety of euchromatic positions by successive series of chromosomal rearrangements. The function of the rl gene is severely affected in rearrangements in which the rl gene is isolated in a small block of heterochromatin, and these position effects can be reverted by rearrangements which bring the rl gene closer to any large block of autosomal or X chromosome heterochromatin. There is some evidence that five other 2R heterochromatic genes are also affected among these rearrangements. These findings demonstrate that the heterochromatic genes, in contrast to euchromatic genes whose function is inhibited by relocation to heterochromatin, require proximity to heterochromatin to function properly, and they argue strongly that a major function of the highly repeated satellite DNA, which comprises most of the heterochromatin, is to provide this heterochromatic environment.

A universal karyotypic system for hexaploid and diploid Avena species brings oat cytogenetics into the genomics era

2021 ◽  
Author(s):  
Wenxi Jiang ◽  
Chengzhi Jiang ◽  
Weiguang Yuan ◽  
Meijun Zhang ◽  
Zijie Fang ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Repetitive Sequences ◽  
Identification System ◽  
Chromosome Identification ◽  
Nomenclature System ◽  
Chromosome Translocations ◽  
C Banding ◽  
Group Assignment ◽  
Standard Karyotype

Abstract Background The identification of chromosomes among Avena species have been studied by C-banding and in situ hybridization. However, the complicated results from several cytogenetic nomenclatures for identifying oat chromosomes are often contradictory. A universal karyotyping nomenclature system for precise chromosome identification and comparative evolutionary studies would be essential for genus Avena based on the recently released genome sequences of hexaploid and diploid Avena species. Results Tandem repetitive sequences were predicted and physically located on chromosomal regions of the Avena sativa genomes. Thirteen new oligonucleotide (oligo) probes for sequential fluorescence in situ hybridization (FISH) were designed and then applied for chromosome karyotyping on mitotic metaphase spreads of eleven hexaploid and diploid Avena accessions. We established a high resolution standard karyotype of A. sativa based on the distinct FISH signals of multiple oligo probes. FISH painting with bulked oligos, based on wheat-barley collinear regions, was used to validate the linkage group assignment for individual A. sativa chromosomes. We integrated our new Oligo-FISH based karyotype system with earlier karyotype nomenclatures through sequential C-banding and FISH methods, then subsequently determined the precise breakage points of some chromosome translocations. Conclusion This new universal chromosome identification system will be a powerful tool for describing the genetic diversity, chromosomal rearrangements and evolutionary relationships among Avena species by comparative cytogenetic and genomic approaches.

scholarly journals A universal karyotypic system for hexaploid and diploid Avena species brings oat cytogenetics into the genomics era

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenxi Jiang ◽  
Chengzhi Jiang ◽  
Weiguang Yuan ◽  
Meijun Zhang ◽  
Zijie Fang ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Repetitive Sequences ◽  
Identification System ◽  
Chromosome Identification ◽  
Nomenclature System ◽  
Chromosome Translocations ◽  
C Banding ◽  
Group Assignment ◽  
Standard Karyotype

Abstract Background The identification of chromosomes among Avena species have been studied by C-banding and in situ hybridization. However, the complicated results from several cytogenetic nomenclatures for identifying oat chromosomes are often contradictory. A universal karyotyping nomenclature system for precise chromosome identification and comparative evolutionary studies would be essential for genus Avena based on the recently released genome sequences of hexaploid and diploid Avena species. Results Tandem repetitive sequences were predicted and physically located on chromosomal regions of the released Avena sativa OT3098 genome assembly v1. Eight new oligonucleotide (oligo) probes for sequential fluorescence in situ hybridization (FISH) were designed and then applied for chromosome karyotyping on mitotic metaphase spreads of A. brevis, A. nuda, A. wiestii, A. ventricosa, A. fatua, and A. sativa species. We established a high-resolution standard karyotype of A. sativa based on the distinct FISH signals of multiple oligo probes. FISH painting with bulked oligos, based on wheat-barley collinear regions, was used to validate the linkage group assignment for individual A. sativa chromosomes. We integrated our new Oligo-FISH based karyotype system with earlier karyotype nomenclatures through sequential C-banding and FISH methods, then subsequently determined the precise breakage points of some chromosome translocations in A. sativa. Conclusions This new universal chromosome identification system will be a powerful tool for describing the genetic diversity, chromosomal rearrangements and evolutionary relationships among Avena species by comparative cytogenetic and genomic approaches.

scholarly journals Involvement of Very Short DNA Tandem Repeats and the Influence of the RAD52 Gene on the Occurrence of Deletions in Saccharomyces cerevisiae

Genetics ◽  
2000 ◽  
Vol 156 (2) ◽  
pp. 549-557 ◽  
Author(s):  
Anne J Welcker ◽  
Jacky de Montigny ◽  
Serge Potier ◽  
Jean-Luc Souciet
Keyword(s):  
Fusion Proteins ◽  
Tandem Repeats ◽  
Chromosomal Rearrangements ◽  
Reversion Rate ◽  
Wild Type ◽  
Recombination Mechanism ◽  
Nonhomologous Recombination ◽  
Deletion Rate ◽  
Dna Tandem Repeats

Abstract Chromosomal rearrangements, such as deletions, duplications, or Ty transposition, are rare events. We devised a method to select for such events as Ura+ revertants of a particular ura2 mutant. Among 133 Ura+ revertants, 14 were identified as the result of a deletion in URA2. Of seven classes of deletions, six had very short regions of identity at their junctions (from 7 to 13 bp long). This strongly suggests a nonhomologous recombination mechanism for the formation of these deletions. The total Ura+ reversion rate was increased 4.2-fold in a rad52Δ strain compared to the wild type, and the deletion rate was significantly increased. All the deletions selected in the rad52Δ context had microhomologies at their junctions. We propose two mechanisms to explain the occurrence of these deletions and discuss the role of microhomology stretches in the formation of fusion proteins.

SINE-B1 Distribution and Chromosome Rearrangements in the South American Proechimys gr. goeldii (Echimyidae, Rodentia)

2021 ◽  
pp. 1-8
Author(s):  
Naiara P. Araújo ◽  
Radarane S. Sena ◽  
Cibele R. Bonvicino ◽  
Gustavo C.S. Kuhn ◽  
Marta Svartman
Keyword(s):  
Transposable Element ◽  
Genome Evolution ◽  
Significant Role ◽  
Sex Chromosomes ◽  
Chromosomal Rearrangements ◽  
Evolutionary Relationship ◽  
Chromosome Rearrangements ◽  
South American ◽  
Gross Chromosomal Rearrangements

<i>Proechimys</i> species are remarkable for their extensive chromosome rearrangements, representing a good model to understand genome evolution. Herein, we cytogenetically analyzed 3 different cytotypes of <i>Proechimys</i> gr. <i>goeldii</i> to assess their evolutionary relationship. We also mapped the transposable element SINE-B1 on the chromosomes of <i>P.</i> gr. <i>goeldii</i> in order to investigate its distribution among individuals and evaluate its possible contribution to karyotype remodeling in this species. SINE-B1 showed a dispersed distribution along chromosome arms and was also detected at the pericentromeric regions of some chromosomes, including pair 1 and the sex chromosomes, which are involved in chromosome rearrangements. In addition, we describe a new cytotype for <i>P.</i> gr. <i>goeldii</i>, reinforcing the significant role of gross chromosomal rearrangements during the evolution of the genus. The results of FISH with SINE-B1 suggest that this issue should be more deeply investigated for a better understanding of its role in the mechanisms involved in the wide variety of <i>Proechimys</i> karyotypes.

scholarly journals The Role of RNA in DNA Breaks, Repair and Chromosomal Rearrangements

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 550
Author(s):  
Matvey Mikhailovich Murashko ◽  
Ekaterina Mikhailovna Stasevich ◽  
Anton Markovich Schwartz ◽  
Dmitriy Vladimirovich Kuprash ◽  
Aksinya Nicolaevna Uvarova ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Gene Mutations ◽  
Nonhomologous End Joining ◽  
Published Data ◽  
Dna Double Strand Breaks ◽  
Dna Breaks ◽  
End Joining ◽  
Homology Directed Repair ◽  
Chromosome Aberration Frequency

Incorrect reparation of DNA double-strand breaks (DSB) leading to chromosomal rearrangements is one of oncogenesis’s primary causes. Recently published data elucidate the key role of various types of RNA in DSB formation, recognition and repair. With growing interest in RNA biology, increasing RNAs are classified as crucial at the different stages of the main pathways of DSB repair in eukaryotic cells: nonhomologous end joining (NHEJ) and homology-directed repair (HDR). Gene mutations or variation in expression levels of such RNAs can lead to local DNA repair defects, increasing the chromosome aberration frequency. Moreover, it was demonstrated that some RNAs could stimulate long-range chromosomal rearrangements. In this review, we discuss recent evidence demonstrating the role of various RNAs in DSB formation and repair. We also consider how RNA may mediate certain chromosomal rearrangements in a sequence-specific manner.

scholarly journals Double labeling of SIgG+ cells harboring a lymphotropic herpesvirus by avidin-biotin complex immunoperoxidase and immunogold-silver staining techniques.

1988 ◽  
Vol 36 (9) ◽  
pp. 1187-1189 ◽  
Author(s):  
Z Nagy-Oltvai ◽  
T Brady ◽  
G D Hsiung
Keyword(s):  
Cell Surface ◽  
Silver Staining ◽  
Simultaneous Detection ◽  
Double Labeling ◽  
Tissue Sections ◽  
Surface Immunoglobulin ◽  
Staining Techniques ◽  
Double Immunolabeling ◽  
Usual Order ◽  
Avidin Biotin Complex

By reversing the usual order of double-staining procedures, we obtained optimal conditions for simultaneous detection of guinea pig lymphotropic herpesvirus (GPHLV) and surface immunoglobulin G-positive (SIgG+) cells in paraffin-embedded tissue sections. Of the different fixatives tested, Bouin's solution gave the best preservation of morphology and cell surface IgG. Double immunolabeling was best achieved when avidin-biotin complex immunoperoxidase (ABC-IP) staining was performed first for detection of intracellular viral antigen, followed by immunogold-silver staining (IGSS) for localization of cell surface IgG.

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